Thermally active mechanically blooming artificial flower

ABSTRACT

The Thermally Active Mechanically Blooming Artificial Flower is an amusement device designed to open autonomously with exposure to sunlight and to close when cooled to ambient temperature. This device includes a novel application of Zylon cable and steel or plastic springs, in a thermomechanical actuator capable of producing torque and angular displacement with changes in temperature. The invention has a series of mechanical systems which translate the motion of the thermomechanical actuator into the opening and closing motion of a pattern of artificial flower petals.

CROSS REFERENCE TO RELATED APPLICATIONS

The application for non-provisional patent refers to a prior provisional patent application by Charles Zachary Henry Application No. US61/137,123 with filing date Jul. 28 2008.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

The invention by Charles Zachary Henry has no other sponsored or supporting individuals or organizations.

BACKGROUND OF THE INVENTION

The Thermally Active Mechanically Blooming Artificial Flower by Charles Zachary Henry is intended to be an autonomous and long-lasting mechanism which responds to changes in its environment. The thermally active mechanically blooming artificial flower (hereafter abbreviated TAMBAF) may be classified according to U.S. Patent Classification Definitions as a member of class 446 Amusement Devices: Toys.

Three primary design rationale for the TAMBAF motivated the design are 1. The TAMBAF should be capable of mechanical action which opens and closes a series of artificial flower petals; 2. The TAMBAF should be capable of autonomous movement requiring no physical human interaction other than construction and maintenance; and 3. The TAMBAF should be capable of lasting for a period of time comparable to a human lifetime and preserve its capability of mechanical action.

The TAMBAF includes a significant, non-obvious, novel, and useful submechanism the Torque and Angular Displacement Producing Temperature Dependent Thermomechanical Actuator (hereafter abbreviated TMA or referred to as thermomechanical actuator). The TMA may be classified according to U.S. Patent Classification Definitions as a member of class 185 Motors: Spring, Weight, or Animal Powered and subclass 10 which signifies a means of winding. The TMA was invented in the process of inventing the TAMBAF which provides support for the three primary design rationale.

BRIEF SUMMARY OF THE INVENTION

The TAMBAF is composed of four submechanisms: 1. enclosure and system of physical supports; 2. TMA; 3. angular motion to linear motion transducer; and 4. flower petal linkage. The design of the TAMBAF is dependent on the inclusion of each of these four submechanisms, but the design does not dictate the exact configuration of each submechanism. Each submechanism must provide the function which it is intended to provide.

The enclosure is designed to rest stably on a flat surface with fixture to physical supports which hold TAMBAF components in a specific range of physical orientation by fixture or by contact. The enclosure contains a reservoir of air or another fluid which is in contact with the TMA. The enclosure serves the purpose of collecting heat and transferring heat to the TMA. The enclosure is designed to collect heat from light by means of infrared, visible, and ultraviolet light absorbing materials or light absorbent surface treatments on structural materials.

The TMA is a coil composed of two materials having different coefficients of thermal expansion and an adjustment mechanism which produces differential longitudinal stress on the two materials. The two materials are attached at one end by fixture to a central axle housed inside the enclosure and supported by bearings supported by the enclosure and system of physical supports. The two materials comprising the coil are designated M1 and M2 in which material M2 is wrapped on the surface of material M1. Material M2 is thus always physically located radially outward from material M1. Material M1 must have a greater coefficient of thermal expansion than material M2. Material M2 is longer than material M1. Material M1 is formed or bent into a coil and has the characteristics of a spring. One end of material M1 is designated the inner end fixed to the axle and the other end is designated the outer end fixed to the enclosure and located physically outward in a horizontal plane from the inner end. One end of material M2 is designated the inner end fixed to the axle. Material M2 wraps around material M1 longitudinally; the end of material M2 opposite the axle is designated the outer end. The outer end is fixed to an adjustment mechanism supported by the enclosure. The adjustment mechanism is operated by human physical interaction and the adjustment mechanism displaces the outer end of material M2 relative to the outer end of material M1. When the temperature of materials M1 and M2 increases, changes in length of materials M1 and M2 results in induced thermal stress in materials M1 and M2. The induced thermal stress in materials M1 and M2 is distributed longitudinally, such that material M1 is in a state of longitudinal compression and material M2 is in a state of longitudinal tension. The induced thermal stresses result in torque transmitted between the enclosure and axle by materials M1 and M2. The axle is free to rotate and rotates through a certain amount of angular displacement dependent on the torque transmitted by materials M1 and M2 and the mechanical loading of the axle by the angular motion to linear motion transducer.

The angular motion to linear motion transducer consists of three plates with slots and a roller which fits into the slots. Two of the plates are designated guide plates which are held fixed to the enclosure by means of vertical physical supports. The guide plates have linear slots which are oriented radially outwards. The third plate of the angular motion to linear motion transducer is designated the translator plate. The translator plate is attached by fixture to the axle in a horizontal plane above the enclosure. The translator plate has curved slots, and each slot in the translator plate is arranged as a portion of a spiral. In each possible angular position of the translator plate, each roller is constrained from moving radially outwards by the slots in the translator plate and the roller is constrained from moving tangentially by the slots in the guide plates. With changes in the angle of the translator plate, the roller moves radially inwards or outwards. Hence, the angular motion to linear motion transducer produced linear movement of the rollers with angular motion of the attached axle. The top plate of the TAMBAF is held fixed by means of vertical physical supports parallel to the enclosure and parallel to the rotary motion to linear motion transducer. The top plate has a series of radial slots and a bracket attached physically outward at the end of each slot. Each roller attaches to a slider which is a component of a flower petal linkage.

The flower petal linkage is a modified form of a slider-crank linkage. Each slider has two parallel grooves which fit into the radial slots of the top plate. The sliders are free to move radially inwards and outwards and are constrained from moving tangentially. Each slider attaches to a connecting link for which one end is free to rotate in a hole in the slider. The hole in each slider is oriented in a horizontal plane at a 90 degree angle to the axis of motion of the slider. The other end of the connecting link attaches to a hole in a lever arm and each lever arm is connected to an artificial flower petal which protrudes upwards and outwards from the top plate. The brackets attached to the top plate support horizontal pins. Each lever arm has a interior closed curved slot which rests on a pin supported by a bracket. For each position of the slider, the lever arm is free to pivot outwards. Each lever arm and its attached artificial flower petal balances on the pin with angular orientation dependent on the location of the center of gravity of the lever arm and its attached artificial flower petal. Inwards movement of the slider moves one end of the connecting link inwards, and the connecting link pulls the lower end of the lever arm inwards. Thus, the inwards movement of the slider causes the balance of the lever arm and its attached artificial flower petal to change. The artificial flower petal pivots outwards on the pin when the slider moves inwards, and the artificial flower petal pivots inwards when the slider moves outwards.

The operation of TAMBAF is thus summarized in the following description: With application of natural or artificial light, the enclosure and thermomechanical actuator become hotter. This creates a torque which is transmitted via central axle to an angular motion to linear motion transducer, which in turn transmits force to a series of sliders. The sliders move inwards and pull inwards one end of a lever arm which attaches to an artificial flower petal. The lever arms are free to pivot outwards on pins which are structurally fixed in place relative to the enclosure. When the sliders move inwards, the artificial flower petals tip outwards under gravity. When the applied light source is no longer present, the enclosure and thermomechanical actuator release heat and become cooler. This creates a torque in the opposite direction as when the TAMBAF becomes hotter. This reverses the direction of movement of the angular motion to linear motion transducer. The sliders move outwards and the connecting links push outwards on the lever arms. When the sliders move outwards, the artificial flower petals tip inwards under gravity. Thus, with every sufficiently large increase in temperature, the TAMBAF produces a mechanical blooming action and with the corresponding decrease in temperature which follows, the TAMBAF produces a mechanical closing action.

DETAILED DESCRIPTION OF THE INVENTION

The amount of energy involved to heat the TAMBAF is low. The enclosure is designed to maximize the heat transferred to the TMA. The design of a mechanism which runs on heat requires that the enclosure act as a reservoir of air or other material which absorbs heat from light or absorbs heat from another material that is designed to maximize absorbed heat from light. The action of the enclosure is to store heat and transmit heat power to the TMA. The capacity of the enclosure is designed to fit the size of the TMA with extra room for expansion of the TMA. The prepared prototype has an enclosure made from polycarbonate with black felt glued to the inside. The Polycarbonate pieces are glued together using high-strength epoxy to for the enclosure.

The TMA is designed to produce torque and create angular displacement with changes in temperature. Two materials, inner material M1 and outer material M2, having different coefficients of thermal expansion are attached at the ends and formed as with thermoset plastics or bent as with metals in the shape of a horizontally oriented spiral. The two materials change length as temperature changes and the difference of the coefficients of thermal expansion between materials M1 and M2 is an important characteristic determining the choice of materials M1 and M2. The two materials are shaped into a coil in direct contact with each other and the outer material M2 having a lower coefficient of thermal expansion than inner material M1.

The size of materials M1 and M2 should be chosen to maximize the differential angular displacement with respect to temperature and length. The equivalent cross-sectional area of a material is the measure of the cross-sectional area of that material subtracting the area of non-material spaces from the geometric cross-sectional area. Materials M1 and M2 have equivalent cross-sectional areas, ECSA1 and ECSA2, and moduli of elasticity E1 and E2. The product of ECSA1 and E1 should be less than or equal to the product of ECSA2 and E2.

General guides for the selection of materials m1 and m2 follow here: The desired amount of angular displacement for a given change of temperature can be achieved by making the length of materials M1 and M2 to an appropriate length. The total angular displacement is proportional to the length of M1 and M2. The desired amount of torque for a given change of temperature can be achieved by making the materials to an appropriate equivalent cross sectional area. Proportionally increasing the equivalent cross-sectional area of materials M1 and M2 increases the torque produced. Thus, it is possible for any choice of materials M1 and M2, having different coefficients of thermal expansion to produce any arbitrary amount of torque and angular temperature for a given change in temperature by choosing the length and equivalent cross-sectional area of materials M1 and M2. A larger difference in coefficient of thermal expansion allows the materials to achieve the desired amount of angular displacement and torque using less total material.

The optimal choice of material M1 is 1074/1075 Tempered Scaleless steel, known by its trade name Scaleless Blue. This steel shows excellent corrosion resistance, high yield strength, and a high modulus of elasticity. Most importantly, 1074/1075 steel has a coefficient of thermal expansion of 11.6 ppm/(degree Celsius). Material M1 can also be chosen as a thermoset plastic, having clear advantages in mass production. The optimal choice of material M2 is Zylon cable, a woven yard made of Zylon filaments, which is patented and produced by Toyobo Co., LTD. Zylon cable has a coefficient of thermal expansion of −6 ppm/(degree Celsius). The TMA presents a new use of Zylon cable which uses Zylon and 1074/1075 steel to produce torque and angular displacement with changes in temperature.

The materials M1 and M2 attach by fixture to a vertically oriented axle. The outer end of material M2 is attached to an adjustment mechanism. The adjustment mechanism is composed of an adjustment slider and an adjustment screw. The adjustment screw is held fixed in place while being free to rotate within the enclosure. Material M2 attaches by fixture to the adjustment slider, and threads on the adjustment slider engage threads on the adjustment screw. The rotation of the adjustment screw moves the adjustment slider relative to the outer end of material M1. The two materials are pre-tensioned by turning the adjustment screw. Pre-tensioning ensures that changes in angular displacement and torque with respect to temperature is linear.

The enclosure and system of physical supports are an essential part of the design of the TAMBAF. The enclosure provides support or fixture for all other components of the TAMBAF. The enclosure supports the axle in two locations with a thrust bearing from below the axle and a roller bearing attached to the top lid of the enclosure. The top lid of the enclosure has a recessed counter-bore which holds the roller bearing in place and a retaining bracket with counter-bore attaches the bearing from above the lid. The axle protrudes above the enclosure and through the retaining bracket. The top lid has tapped holes which attaches the system of supports above the enclosure. A series of spacers support the angular motion to linear motion transducer. The top plate is attached with bolts which run through the spacers and screw into the top lid of the enclosure. The top plate supports the flower petal linkage.

The angular motion to linear motion transducer is designed to produce a designed amount of linear motion and force from a designed amount of angular motion and torque. The guide plates constrain the rollers tangentially above and below the translator plate, preventing the rollers from tilting at an angle. The translator plate moves the rollers radially inwards or outwards by rotating relative to the guide plates. The slots in the translator plate are designed well using polar coordinates. The spiral shape of the slots is a function R(theta) that maps a change in angle (theta) to a change in radius. The slot geometry is defined as a smooth curve which connects points R(theta_begin)=R begin and R(theta_end)=R_end. The values of theta_begin, theta_end, R_begin, and R_end are variables chosen for the design. The angular displacement is the quantity theta_end minus theta_begin, and the linear displacement is the quantity R_end minus R_begin. The roller is made up of three independent rollers that contact with the translator plate and each of the guide plates separately.

The flower petal linkage is designed to produce an angular change of the artificial flower petals for a given linear displacement of the rollers. The design is a modified slider-crank mechanism. The sliders attach to the rollers and travel through linear displacement R_end minus R_begin. The sliders attach to a connecting link, and the connecting link attaches to the lever arm. The lever arm is designed as a counter-weight to the artificial flower petal. The lever arm and artificial flower petal have combined center of gravity with a known fixed location. The lever arm has a curved slot which rests on a pin supported by brackets supported from the top plate. The curved slot is designed so that the center of gravity becomes vertically above the pin with 30 degrees of angular movement of the lever arm and artificial flower petal. When the center of gravity is vertically above the pin, the curved slot in the lever arm is free to move relative to the pin. This allows the lever arm and artificial flower petal to act as a mechanical switch, where a large change of angle is possible for a small linear displacement of the slider. 

1. Torque and Angular Displacement Producing Temperature Dependent Thermomechanical Actuator, comprised of a length of stiff elastic material, either steel or thermoset plastic, formed or bent into a planar spiral as a spring a length of Zylon cable, which wraps longitudinally on the outer facing surface of the spring an axle which attaches to the spring and cable and an adjustment mechanism capable of inducing longitudinal tension in the Zylon cable and longitudinal compression in the spring by displacing the outer ends of the cable and spring relative to each other.
 2. Thermally Active Mechanically Blooming Artificial Flower, comprised of an enclosure and system of physical supports a torque and angular displacement producing temperature dependent thermomechanical actuator an angular motion to linear motion transducer and a flower petal linkage which converts linear motion into movement of externally supported artificial flower petals 